package cn.yj.admin.verificationCode;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.Random;

/**
 * <p>
 * 验证码生成类
 * </p>
 *
 * @author 永健
 * @since 2020-05-21 22:31:42
 */
public class ValidateCodeUtil
{

    private static ValidateCodeUtil instance;

    public static synchronized ValidateCodeUtil getInstance()
    {
        if (instance == null)
        {
            instance = new ValidateCodeUtil();
        }
        return instance;
    }

    private ValidateCodeUtil()
    {

    }

    /**
     * 放到session中的key
     */
    public static final String RANDOMCODEKEY = "RANDOMVALIDATECODEKEY";

    /**随机产生只有数字的字符串 private String*/
    //private String randString = "0123456789";
    /**随机产生只有字母的字符串*/
    //private String randString = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    /**
     * 随机产生数字与字母组合的字符串
     */
    private String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    /**
     * 图片宽
     */
    private int width = 100;
    /**
     * 图片高
     */
    private int height = 40;
    /**
     * 干扰线数量
     */
    private int lineSize = 40;
    /**
     * 随机产生字符数量
     */
    private int stringNum = 4;

    private static final Logger logger = LoggerFactory.getLogger(
            ValidateCodeUtil.class);

    private Random random = new Random();

    /**
     * 获得字体
     */
    private Font getFont()
    {
        return new Font("Fixedsys", Font.CENTER_BASELINE, 18);
    }

    /**
     * 获得颜色
     */
    private Color getRandColor(int fc, int bc)
    {
        if (fc > 255)
        {
            fc = 255;
        }
        if (bc > 255)
        {
            bc = 255;
        }
        int r = fc + random.nextInt(bc - fc - 16);
        int g = fc + random.nextInt(bc - fc - 14);
        int b = fc + random.nextInt(bc - fc - 18);
        return new Color(r, g, b);
    }

    /**
     * 生成随机图片
     */
    public void createRandom(HttpServletRequest request, HttpServletResponse response)
    {
        // BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
        // 产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作
        Graphics g = image.getGraphics();
        //图片大小
        g.fillRect(0, 0, width, height);
        //字体大小
        g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));
        //字体颜色
        g.setColor(getRandColor(110, 133));
        // 绘制干扰线
        for (int i = 0; i <= lineSize; i++)
        {
            drowLine(g);
        }
        // 绘制随机字符
        String randomString = "";
        for (int i = 1; i <= stringNum; i++)
        {
            randomString = drawString(g, randomString, i);
        }

        LocalVerificationCodeSaveType.save(randomString, request);

        g.dispose();
        try
        {
            // 将内存中的图片通过流动形式输出到客户端
            ImageIO.write(image, "JPEG", response.getOutputStream());
        } catch (Exception e)
        {
            logger.error("将内存中的图片通过流动形式输出到客户端失败>>>>   ", e);
        }
    }

    public String getExitsCode(HttpServletRequest request)
    {
        return LocalVerificationCodeSaveType.get(request.getSession());
    }


    /**
     * 绘制字符串
     */
    private String drawString(Graphics g, String randomString, int i)
    {
        g.setFont(getFont());
        g.setColor(new Color(random.nextInt(101), random.nextInt(111), random
                .nextInt(121)));
        String rand = String.valueOf(getImgCode(random.nextInt(randString
                .length())));
        randomString += rand;
        g.translate(random.nextInt(3), random.nextInt(3));
        g.drawString(rand, 13 * i, 16);
        return randomString;
    }

    /**
     * 绘制干扰线
     */
    private void drowLine(Graphics g)
    {
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        int xl = random.nextInt(13);
        int yl = random.nextInt(15);
        g.drawLine(x, y, x + xl, y + yl);
    }

    /**
     * 获取随机的字符
     */
    public String getImgCode(int num)
    {
        return String.valueOf(randString.charAt(num));
    }

}
